July 2012World Premiere!
Pro Audio Bono PAB SE AP Alu Anti-Vibration PlatformWithout this kind of high quality isolation accessories we miss out on a lot of music!Review
By Wojciech Pacuła

Reducing
vibration is a fairly well-documented method of distortion reduction in
electronic devices. The techniques allowing to minimize this phenomenon or, more
accurately, to control it (that is, to minimize it in a controlled, predefined
way) are completely normal for such demanding applications as military or
medicine. In audio world, the measures to reduce this type of distortion have
been known for a long time, and implemented both in turntables as well as tube
amplifiers designs. With a growing popularity of the new invention which was the
transistor and the later success of the CD format, eventually taking over the
market, it seemed that at least this one problem was gone once for all and we
could move on. After all, transistors all but eliminated microphony, while the
optical reading of the signal combined with advanced read error correction
mechanism in CD seemed to be
ideally immune to any external influence. Well, it was true while it lasted.

For
soon enough the perfectionists, i.e. audiophiles (or, as my friends says,
enlightened music lovers) came to the conclusion that the mechanical design of
any audio component, be that a solid state amplifier or a CD player, have
significant influence on the final effect, that is sound. This in turn meant
that the problem caused by vibration was not fully resolved and – perhaps –
new problems were introduced which, to some extent, had been overcome in the
previous generation of devices. The need to fight them gave rise to the number
of manufacturers offering racks, platforms, stands, feet, spacers, cones, and
many other products designed to minimize vibration.

One of such manufacturers is Pro Audio Bono
(acronym PAB), located in Piaseczno near Warsaw (Warsaw, let me remind you, is
the capital of Poland) and run by an engineer, Mr. WladyslawSkrzypczak
(difficult name, I admit, but we the Poles just love this type of spelling
conundrums...). The owner-designer's profession is important, because it shows
that vibrations, resonances, their influence on sound as well as possible ways
to counter them, are not the domain of madmen or stoners tripped out on weed,
but rather a normal exercise in physics. Reputable manufactures confirm it with
proper measurements – the Japanese excel in this, to name Acoustic Revive,
fo.Q, or Audio Replas (they all actually collaborate), but VertexAQ from the UK
also made remarkable progress. What they all have in common is their scientific
approach to the subject matter, the fact that they employ engineers in the role
of designers, and maintain close contacts with universities as well as defense
and medical industry. Not to mention the measurements that accompany each of
their products.

The first time I came across PAB's products was
in the middle of 2010, shortly after the company's debut. I was then preparing a
review of anti-vibration accessories for the Polish magazine Audio
and among some very expensive components, such as a rack and accessories from
the Japanese Harmonix, there was also the Pro Audio Bono isolation platform.
Intrigued by its design, as well as obvious concept similarities to the racks
from another manufacturer, String Suspension Concept, I invited Mr. Skrzypczak
for a visit and I asked him about this and that.

Design
Concept

PAB platforms are based on the idea of mechanical
decoupling of two boards – the top shelf which hosts our audio component is
suspended above and decoupled from the base shelf. This design concept is
exactly what matters here: the two surfaces are mechanically decoupled from each
other, here by means of nylon cords on which the top shelf is suspended. Of
course the idea is well known and used in turntables, most notably the SME20 and
SME30 from SME Limited. Their design also features two shelves, decoupled by
multiple rubber rings. What is common with the PAB design is the mounting
mechanism: the base shelf holds a kind of posts – four metal tubes protruding
a couple of inches above the top shelf which is suspended on the rings (SME) or "strings"
(PAB), attached to the top of the posts. That's all there is to it. The Polish
platform design is somewhat more complex, although not by much. The "strings"
are thin nylon cords, selected from among dozens of other materials. They needed
to be durable, with good damping properties, and could not deform (lengthen)
over time. They are not attached permanently to the posts, but rather pass
through pulleys and return back down to the tensioning mechanism. Each "tensioner"
is made of a machine head used for adjusting string tension in stringed musical
instruments. The platform needs to be leveled and then strung so that the top
shelf were as low as possible, but not in contact with the base shelf. Such is
the basic PAB concept, as applied to both their anti-vibration platforms as well
as speaker stands and anti-vibrations racks. It has common features with the SSC
design, however it differs in many details, for as Mr. Skrzypczak says, his
continuous research and measurements show the new areas for improvement.

I reviewed the first version of the PAB isolation
platform in 2010; it featured thin shelves, regular feet, brass tube posts and
friction bearings. Another one I bought for myself had thick shelves. After
about a year Mr. Skrzypczak kindly replaced its friction bearings for rolling
bearings. The newest version which is the subject of this review comes with
thick shelves, roller bearings and two innovations: posts made of aluminum tube
instead of brass and completely new, bearing based anti-vibration feet,
replacing ordinary brass ones. This version is called PAB SE Alu AP (double
plywood, large shelf, veneer, foil or paint). You can also purchase the optional
PAB bearing AF feet (‘AF' stands for ‘anti-vibration foot'), which we'll
have a look at as well. The feet feature self-aligning bearings in metal (brass)
housing; their load capacity, depending on the version, is up to 60 kg or 120 kg
(130 or 260 lbs.). Unlike other designs using rolling bearings, the innovation
lies in the fact that the upper (carrier or working) part of the foot does not
rest on the bearing balls, but is suspended on them (patent pending).

Test
MethodologyAs always, testing methodology is equally
important as the test itself. My test methodology hasn't significantly changed
over the past dozen years. I have improved some details but the basics have
remained for they are well proven. What I do is compare the tested component
with my reference component in an A/B/A comparison with A and B known, first
using two minutes music samples and, in the end, full albums. I do not employ
ABX tests for – as confirmed by my several years of experience during our
Krakow Sonic Society meetings – they are useless in case of music and their
results are inconclusive. In contrast, even short A/B comparison can show sonic
differences.

A few words are due on what the ‘reference' is.
The Oxford English Dictionary defines it as "denoting an object, property,
value, or the like, used as a basis for comparative measurement or
standardization." It also mentions "absolute reference." The former simply
describes comparing two values or components, without taking into account the
quality of the reference component. What is important is that it is a known
value. The latter speaks of the possibly ultimate component, known and chosen
because of its highest quality. In audio these two definitions are often
confused.

In case of Pro Audio Bono I employed both
‘references'. The first reference was the shelf of my Base rack. The rack
consists of a frame made of thick-walled metal tubes filled with oil, supporting
layered shelves made of MDF and plywood, with a layer of special glue formula
and Japanese paper sandwiched between the two. The shelves are decoupled from
the frame with boron carbide spikes (cones) and quartz spacers, similar to
RIQ-5010W spacers from Acoustic Revive. The ultimate reference for me is the
Acoustic Revive RAF-48H air floating board under the Ancient Audio Lektor Air
V-edition CD player and the Audio Research Ref5 SE preamplifier on the one hand,
and the PAB SE AP platform under the Leben CS-300 XS [Custom Version] headphone
amplifier, on the other.

SoundPAB SE Alu AP
Versus Acoustic Revive RAF-48H

My main interest was a direct comparison of the PAB platform with the Acoustic
Revive RAF-48H air floating board. As it turned out, the sonic differences
between them, although discernible, were however more nuanced than I'd expected,
that is smaller than between the PAB platform with brass feet and the AR air
floating board. Still, they were there.

The Japanese board helps the electronics to
slightly better form the sound attack and to clearer present the instrument
shapes. Likewise, texture differentiation, all those small characteristics
together forming the ‘sonics' of the given sound source, were slightly better
with the RAF-48H. The key word however being slightly.
For the Japanese platform is actually much more expensive, requires periodic
inflating and is a true reference. The differences were not so much structural,
as both platforms shape the sound in a similar way, but rather superficial, as
if the same base framework was filled in each case with slightly different
content.

But the differences were there. The Polish
platform somewhat rounds the treble, withdrawing it gently. It was audible with
Sara K.'s vocal on her solo concert CD Don't
I Know You from Somewhere? [Stockfisch SFR 357.6055.2]. On this album
she accompanies herself on a special, four-string guitar. Typically for
Stockfisch, the recording is outstanding but there are still some limitations
inherent to live concert production. One of them is a slight accentuation of the
sibilants, forced I think by the particular stage microphone choice. It is not
irritating or particularly disrupting but with the RAF-48H we know where it
comes from, what could be its origin, and we take it together with "the whole
package." The PAB board smoothed out this sub-range. The microphone sonic
signature was not as well audible as before. But, to put it into perspective:
the difference was minor, more of a slight shift of accentuation than a
significant alteration. Correspondingly, it was also noticeable with electronic
music, for example the remixes of the track "Personal Jesus" by Depeche Mode
[Mute, CDBONG43]. Here, additionally appeared a small warming up of sound, not
so apparent earlier.

However,
there was an area where the Polish platform fared better – midbass control.
Both isolation boards show exemplary bass range. Stiff, mass market racks and
shelves usually thin up the sound in the bottom end, taking something away with
it. They give instead precision and timing but, I think, only because there is
less to control, not that they bring some real improvement. In this respect –
again, in my opinion – "springy" boards come up on top. Both platforms are
top-notch contenders. Still, the PAB platform brings something extra, i.e. it
shows the midbass with more precision, without any thinning up or drying up.
This is the double bass sonic range, and the improvement was evident for example
on the "After Hours" album by André Previn, newly remastered by Winston Ma for
his First Impression Music record label (Lasting Impression Music, LIM UHD 051;
these are re-editions of Telarc CDs and this particular album cover features a
reproduction of the award from High Fidelity magazine, where I am the
chief editor – so why I shouldn't mention it...). Likewise, Joe Pass's
acoustic guitar seemed more focused, not (slightly) sloppy as before.

PAB
SE Alu AP Versus NothingHaving listened to music for several years with
my CD player sitting on the Acoustic Revive isolation board (first the RAF-48,
currently the RAF-48H) and with the PAB SE AP platform under my Leben CS-300 XS
Custom Version headphone amplifier, I have apparently forgotten what these
components bring to my system. From time to time, reviewing other isolation
boards I am suddenly made acutely aware of that fact, but the rest of time I
live in blissful ignorance, taking THIS sound for granted, as my reference
sound.

A quick comparison of the PAB platform with the
audio components sitting straight on the rack shelf, with no isolation board
whatsoever, was more than enough to make me shout loud and clear: without
this kind of high quality isolation accessories we miss out on a lot of music!
And yet my rack is nothing to sneeze at; thick-walled tube frame made of special
steel, filled with oil, custom shelves made of sandwiched MDF and plywood,
decoupled with quartz spacers… But I cannot turn the blind eye (or rather ear)
to what I hear: the PAB platform, similarly to the AR, brings a lot of life to
music.

For the fact that both platforms change the
sonics, lowering it, that they eliminate the tremor of the top end correcting
its overly bright character, which they make the bass full-bodied with nice
texture – these are all important improvements but not as vital as something
that is more general in nature. With this particular version of the PAB
platform, that is one with thick shelves, bearing based suspension and aluminum
feet we get a much better colored, a much more "muscular" presentation. Take the
platform away and the sound seems anemic and withdrawn. I know that such sharp
differentiation disappears over time and sitting our audio components directly
on the rack shelves and living with that sound, we eventually get used to it.
Still however, sitting the CD player or our preamp back on the isolation board
turns everything upside down, as if some kind of window re-opened in our mind.

It is a very fleshy but well controlled sound.
Remarkably vital in the sense that it is agile, never sounding lazy. Lower mids
and the midrange in general are accentuated while the treble is slightly warmed
up. Not to the extent that it masks anything – when the orchestra breaks in on
the new "Valtari" album by SigurRós [EMI Records Limited 6235552] it sounds
big, full, unmuffled. Similarly, when the drums enter on the 301 album by
e.s.t. [ACT 9029-2], the cymbals are resonant and have proper weight.

PAB
Bearing AF Versus Classic Feet

Finally, a few words on the sonic difference between
classic feet and the PAB bearing AF feet. As with any mechanical change, this
one also has influence on sound. The improved PAB feet open up the sound,
helping to show deeper sound stage. The differences are not as marked as those
between the PAB platform and a typical rack shelf, but they are nevertheless
positive and evident. The excellent timbre and texture remain, with added
‘breath', or ‘air'. It's well worth trying!

Conclusion

In
the end, no longer can you live without a good isolation platform. It brings the
most marked improvement in case of digital players, including network audio
players (sic!), followed by preamplifiers, and finally power and integrated
amplifiers – no matter whether tube or solid state. It has a cumulative
effect, i.e. positive changes in individual components of the hi-fi chain all
add up and the improvements accumulate. It is unequivocally a good direction and
I for one cannot imagine listening to music without good platforms. Whether it
be the very expensive Acoustic Revive board or the astronomically priced
Harmonix system, the choice is all yours. But even if you are not fully
convinced at this point or you simply like experimenting, you need to try out
the newest version of the Pro Audio Bono platform; you will be in for a surprise
how much your system's sound can be improved for a comparatively modest price.
That remains true not only for the fat components worth $5000 to $10,000 but
also those modest $500 pieces – you have my word for it!